The potential energy in water pooled behind a dam is converted to kinetic energy as gravity causes the water to surge through tunnels in the dam.
Potential energy is the energy of position. The potential energy of water behind a dam can be maximized by increasing the difference in height between the water's staring point and the water's outflow point. The more potential energy the water has, the more kinetic energy can be produced when the water is set in motion. This energy of motion can then be used to spin turbines that drive electrical generators, which produce electricity to power homes and businesses. Electrical power produced in this manner is called hydroelectric power.